CYLINDRICAL LITHIUM-ION SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a cylindrical lithium-ion secondary battery having high safety performance and high cycle characteristics under abnormally high temperatures.

SOLUTION: The cylindrical lithium-ion secondary battery is formed by spirally winding a positive plate in which an active material is applied to a belt-shaped current collector and a negative plate in which an active material is applied to a belt-shaped current collector through a separator to constitute a wound group, and sealing the wound group in a metallic outer packaging case together with a nonaqueous electrolyte, the ratio ψ1/ψ2 of the diameter (ψ1) of a space installed in the central part to the outer diameter (ψ2) of the wound group is made 0.20-0.30, and the ratio ψ2/ψ3 of the outer diameter (ψ2) of the wound group to the inner diameter (ψ3) of the battery case is made 0.94-0.97.

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